Here are some thoughts. Transcription isn't a science, and I'm not the best transcriber in the world. Having considered these points, the next step in the tutorial is 'analysis' (link below).
Lines 5-6. Is the whole thing rushed through or just >I get-<? I'm not sure. Probably feels like it is all a bit rushed.
Line 6. 'I've got some change'. Is under-transcribed. It could be produced as a question, i.e., 'I've got some change if you want to buy the magazine', with upwards or continuing intonation. But it is produced with stopping intonation. So you might mark that up with a full stop.
Line 9. He starts up just a tiny bit before she does (at line 8) and says ('yes'I'ave). Is it important? Your call.
Line 12. Basically, I don't do much with this line. I could give the reader more information on whether he is going along with the 'discovery' of not.